The present invention relates to a transmission for single-shaft gas turbine engines for automobiles, particularly passenger cars.
Potentially low costs are stimulating development of a single-shaft gas turbine engine for passenger cars. Against this cost advantage must be balanced the increased cost of providing a transmission that must be carefully matched with the engine and the vehicle to compensate for the inherent torque characteristics of the engine. Torque of the engine is quite small in the low engine revolution range and rises steeply up to the maximum as the engine speed increases. For the engine, a transmission including an hydraulic torque converter followed by a forward-reverse gear box has been proposed. The transmission input element is a torque converter impeller shaft connected directly to the engine shaft, while the output element is a gearbox output shaft drivingly connected to the vehicle driving wheels. As the torque converter has a slippage band, the engine can be started without picking up load. However, since the slippage band is narrow, the engine can not increase its speed without picking up load up to a certain speed range where the engine will develop a torque large enough to start moving the vehicle. Thus difficulty in starting the vehicle moving and unstable performance at low vehicle speeds, resulting frequently in engine stalls, were unavoidable with the conventional transmission. The present invention consists of a transmission avoiding the abovementioned shortcomings of such transmission.